GOBAO ECVT EMTB Mid-Drive Motor

[Diby2000]

In an earlier post, responding to @patdam I was conflating manual transmission as a gearbox (pinion or manual transmission in a car). Maybe not what was being asked. I now believe he was talking about derailleur transmission. My bad.

My thoughts are still that the e-cvt may be benifical here also as mentioned, the existing motor systems already have planetary and or belt speed reduction that is already contributing to some efficiency losses, here they could be the same or even less depending on which part of the planetary is being driven by the motor. The toyota e-cvt confguration is not the only possible configuration available. It has its own design constraints, such as an internal combustion engine that can only spin at a limited rpm, and in only 1 direction. I suggest that the 2 electric motors could drive the internal gears of the planetary (sun and planets) which will inherently provide significant reduction to the system.
Also, I can't remember which thread I mentioned this earlier, but the addition of a 2nd motor does not necessarily mean a loss of efficiency. It verry well could, and probably will/has is early generations of design, but these 2 motors are not both 1500w each, they will possibly be around 1000w and 500w. Remember the torque/power is added/multiplied through the gearing.

 

[Ndanger]

Not much more is required for ECVT besides connecting the extra motor and unshackling the ring gear to connect to the drive motor.

I am new to the concept of e-cvt and just coming to the conclusion that the chain ring rotates at a different cadence than the pedal crank. Interesting...

 

[Astro66]

I am new to the concept of e-cvt and just coming to the conclusion that the chain ring rotates at a different cadence than the pedal crank. Interesting...

This is why, if you set the E-CVT up with say 12 fixed gears. The pedalling should feel almost identical to a 12 speed derailleur, as it doesn't matter if the ratio change between the cranks and rear wheel, is done at the chainwheel, or the cassette.

It's only the ratio between the cranks and rear wheel that determines the feedback to your legs.

 

[jeanjean]

E2drive patents already show several potential ecvt configurations.

Google Patents

Search and read the full text of patents from around the world with Google Patents, and find prior art in our index of non-patent literature.

patents.google.com

Didn't yet check for gobao or avinox patents.

Edit:

Google Patents

Search and read the full text of patents from around the world with Google Patents, and find prior art in our index of non-patent literature.

patents.google.com

Nothing yet found for DJI or avinox

 

[jeanjean]

US20170217537A1 - Bicycle driving device - Google Patents

A bicycle driving device allows control to be executed in accordance with the riding conditions. The bicycle driving device includes a planetary mechanism, a first motor, a second motor, and an output part. The planetary mechanism includes an input body to which rotation of a crankshaft is...

patents.google.com

Shimano, 10 years ago, didn't believe in ecvt...

 

[patdam]

US20170217537A1 - Bicycle driving device - Google Patents

A bicycle driving device allows control to be executed in accordance with the riding conditions. The bicycle driving device includes a planetary mechanism, a first motor, a second motor, and an output part. The planetary mechanism includes an input body to which rotation of a crankshaft is...

patents.google.com

Shimano, 10 years ago, didn't believe in ecvt...

wy you said "shimano didn't believe", as they deposit patents on ECVT in 2017 ? (sorry i'm not fluent in english)

 

[jeanjean]

Well, they didn't bring it to the market.
Maybe they didn't believe that customers would buy this technology.
Maybe they had other reasons not to further develop this technology.

 

[patdam]

Well, they didn't bring it to the market.
Maybe they didn't believe that customers would buy this technology.
Maybe they had other reasons not to further develop this technology.

OK. . Perhaps it was also to block the market launch of this system, which would compete with them ?

 

[DylanJM]

Well, they didn't bring it to the market.
Maybe they didn't believe that customers would buy this technology.
Maybe they had other reasons not to further develop this technology.

10 years ago is a long time in the history of emtb. Remember what they looked like back then and what specs were? Development likely was not advanced enough to bring an eCVT to market back then.

 

[jeanjean]

Then it's time to take this project out of the drawer.
Customers are waiting

 

[Ndanger]

E2drive patents already show several potential ecvt configurations.

Google Patents

Search and read the full text of patents from around the world with Google Patents, and find prior art in our index of non-patent literature.

patents.google.com

Didn't yet check for gobao or avinox patents.

Edit:

Google Patents

Search and read the full text of patents from around the world with Google Patents, and find prior art in our index of non-patent literature.

patents.google.com

Nothing yet found for DJI or avinox

Excellent find!

 

[Ndanger]

I colored gears and put together the flow pattern along with a legend to try and better understand the design and the gear path to the chain ring (which is separate from the crank) as attached. Green is the gear reduction, similar to a derailleur bike, everthing else is the transmission that will effectively replace the derailleur drive train.

 

[slickrock]

I colored gears and put together the flow pattern along with a legend to try and better understand the design and the gear path to the chain ring (which is separate from the crank) as attached. Green is the gear reduction, similar to a derailleur bike, everthing else is the transmission that will effectively replace the derailleur drive train.


View attachment 187821

I colored gears and put together the flow pattern along with a legend to try and better understand the design and the gear path to the chain ring (which is separate from the crank) as attached. Green is the gear reduction, similar to a derailleur bike, everthing else is the transmission that will effectively replace the derailleur drive train.


View attachment 187821

Look at the mechanical extra design required to get power to the chainring that is axial to the pedal axle. If that was relaxed, the design would even be simpler.

 

[slickrock]

I honestly don't know.
There are less moving parts, less gear teeth interactions (more teeth that are actually transmitting torque and this is where most efficientcy losses happen, but less overall), maybe less rotating inertia? In the single planetary gearbox, but you also have 2 electric motors that the manual gearbox does not have.
I think this is not so straight forward a question/statement.

I think more relevant is:
Is a single large powerful motor with a chain and deralleur more efficient than an ecvt and chain/belt/whatever drive system you use to get the power to the rear wheel?
If so, what is the deference and do you think this trade-off is worth the potential benifits of the system?

We will see how multiple ECVTs motor solutions flesh out (don't forget 2025's E2's ECVT, which BTW has been suspiciously silent after the Gabao/Avinox announcements), but my feeling is that for the whole EMTB system (including the rider), ECVT may be actually more efficient that a typical motor/derailleur setup in use, in pretty much in an analogous way Hybrid drive makes HEV cars get better mileage ICE cars:

1. ECVT can keep the motor in its most efficient band of RPM, changing gear ratios to balance torque and cadence, ultimately giving you more range. This is better than typical EMTB eco modes which run the motor at reduced torque or kick in after a lot of pedal torque is applied.
2. ECVT can keep the rider in his/her most efficient band of power delivery. By choosing a consistent pedal cadence/pedal torque balance, you can best convert those calories into forward momentum.
3. Current EMTBs, especially the new powerful ones like the M2, allow people to over drive the motor and over torque the system rather than being in the correct gear to keep drivetrain from blowing up. ECVT puts you in the best gear to keep this from destructive energy loss from happening.
4. Mechanical derailleur changes, gear jumping, cross chaining and other shifting latencies alone add inefficiencies and are more frustrated when the elements/mud come into the picture.
5. AI Greg mentions torque slip with ECVT, but there is gear slip with legacy setups.
6. And finally, battery regen capability. Though this will be harder to implement with current proposed bike designs.

Keep in mind that ECVT can still be put into a mode that puts the motor in its optimum power curve rather than its optimum efficiency curve, so your boost mode can ditch the efficiency mode mode when needed. There's really a ton of flexibility to had with ECVT.

 

[Fangs2k]

ECVT may be actually more efficient that a typical motor/derailleur setup in use, in pretty much in an analogous way Hybrid drive makes HEV cars get better mileage ICE cars:

I’m not sure that’s a very helpful comparison.

Electric motors in ICE cars (hybrids) help with mpg as they’re ’fuel multipliers’, they assist with the hard work to get a car moving for example, a very energy intensive phase in driving.

For e-bikes, the engine is the human, the electric motor is the multiplier and that helps with the energy intensive parts of cycling (uphill etc).

Will an ECVT be more efficient than an equivalent motor and derailleur setup? We don’t know yet, but the basic laws of physics will still apply so I predict you’ll be able to throw a blanket over them.

There are lots of good reasons for ECVTs on EMTBs, not sure efficiency will be the main one.

 

[Red Peekay]

This a short cool video on the concept bikes looking at this motor..

36K views · 543 reactions | Avinox présente aujourd’hui 4 concepts équipés de son prototype de moteur MG Concept, un moteur intégrant une transmission. Pour l’heure, peu d’infos sur ces 4 cadres qui sont eux aussi encore à l’état de prototype. | En

Avinox présente aujourd’hui 4 concepts équipés de son prototype de moteur MG Concept, un moteur intégrant une transmission. Pour l’heure, peu d’infos sur ces 4 cadres qui sont eux aussi encore à...

www.facebook.com

 

[Ndanger]

A traditional derailleur and chain system is incredibly efficient. It has a very straight mechanical path with minimal friction.

Internal gearboxes and CVTs, like those from Gobao, Avinox, rely on complex internal mechanics. E-CVTs usually use a planetary gear setup combined with electric motors to constantly change ratios.

Every time power passes through multiple meshing gears, planetaries, you lose energy to friction and heat. So my next emtb bike will be the most efficient one, with my simple mechanical derailleur. Although my next commuter will be an e cvt

 

[TheKaiser]

A traditional derailleur and chain system is incredibly efficient. It has a very straight mechanical path with minimal friction.

Internal gearboxes and CVTs, like those from Gobao, Avinox, rely on complex internal mechanics. E-CVTs usually use a planetary gear setup combined with electric motors to constantly change ratios.

Every time power passes through multiple meshing gears, planetaries, you lose energy to friction and heat. So my next emtb bike will be the most efficient one, with my simple mechanical derailleur. Although my next commuter will be an e cvt

Existing ebike motors use "complex internal mechanics", "planetary gears", and "multiple meshing gears" too, though, so they're also already "losing energy to friction and and heat". Is it not possible that an eCVT could be designed in such a way that the number of meshing gears isn't drastically increased vs. a traditional ebike motor with standard derailleur? In other words, couldn't the eCVT reposition the arrangement of gears, so the total number is kept similar, but the capabilities are greatly expanded?

 

[Powerslider]

I suggest that the 2 electric motors could drive the internal gears of the planetary (sun and planets) which will inherently provide significant reduction to the system.
Also, I can't remember which thread I mentioned this earlier, but the addition of a 2nd motor does not necessarily mean a loss of efficiency. It verry well could, and probably will/has is early generations of design, but these 2 motors are not both 1500w each, they will possibly be around 1000w and 500w. Remember the torque/power is added/multiplied through the gearing.

That's not how I'm envisioning the orientation. My thinking is there's a 1500W drive motor; and a very small motor dedicated strictly to changing gear ratios.

 

[slickrock]

Existing ebike motors use "complex internal mechanics", "planetary gears", and "multiple meshing gears" too, though, so they're also already "losing energy to friction and and heat". Is it not possible that an eCVT could be designed in such a way that the number of meshing gears isn't drastically increased vs. a traditional ebike motor with standard derailleur? In other words, couldn't the eCVT reposition the arrangement of gears, so the total number is kept similar, but the capabilities are greatly expanded?

Agreed. The Avinox M1 and M2 motors already run internal planetary gears. It's just with ECVT, the sun, planetary, and ring gears are all in motion instead of just two with the M1/M2. It's also why the MG is scarcely larger than the M1/M2. For DJI, ECVT was low-hanging fruit.

That's not how I'm envisioning the orientation. My thinking is there's a 1500W drive motor; and a very small motor dedicated strictly to changing gear ratios.

True, you need that second motor, but the second motor also contributes power output to final drive along with the main motor. This was clearly the case with Revonte ECVT so I suspect it's the same with the new kids on the block.

 

[Ndanger]

Is it not possible that an eCVT could be designed in such a way that the number of meshing gears isn't drastically increased vs. a traditional ebike motor with standard derailleur?

Two possible choices for “not increasing meshing gears” is

1/ scooter type belt and pulley cvt drive (which is hugely inefficient) and 2/ Ball-planetary / Toroidal traction drives come to mind.

Toroidal Drive can replace gear teeth with rolling contact between tilting balls and two discs. The number of contact points is comparable to a planetary hub gear (sun/planet/ring vs disc/ball/disc), so you're not adding a pile of extra meshing elements, you're swapping fixed teeth for adjustable-angle rolling contacts "rolling/sliding losses at these contact points."

 

[Diby2000]

True, you need that second motor, but the second motor also contributes power output to final drive along with the main motor. This was clearly the case with Revonte ECVT so I suspect it's the same with the new kids on the block.

This was my thinking also. And the fact that the second motor needs to be strong (torquie) enough to oppose/control the output of the first motor, although with a gearing advantage. Add this to the torque potentially produced from the human on the pedals.
I guess technically, the second motor does not need to contribute much POWER (torque x rpm) but it will have to produce enough torque to allow control, and enough rpm to produce the gear ratio desired. I think electrical motors that can produce good torque, are still able to rotate at decent speeds, so you ay as well spin it up.

 

[slickrock]

This a short cool video on the concept bikes looking at this motor..

36K views · 543 reactions | Avinox présente aujourd’hui 4 concepts équipés de son prototype de moteur MG Concept, un moteur intégrant une transmission. Pour l’heure, peu d’infos sur ces 4 cadres qui sont eux aussi encore à l’état de prototype. | En

Avinox présente aujourd’hui 4 concepts équipés de son prototype de moteur MG Concept, un moteur intégrant une transmission. Pour l’heure, peu d’infos sur ces 4 cadres qui sont eux aussi encore à...

www.facebook.com

While that post is for the MG instead of the X1P, the innovation is felt just the same. What’s really interesting it the AI camera on the Mondraker prototype:

I’ve test the Rivian/Also TM-B and one of the boatload of high tech features on that bike was its virtual manual shifting mode. I was blown away on how instantaneous and precise it felt (including haptic feedback), and it really made the e-mobility aspect of the bike feel like an actual EMTB on the technical trails. I’m certain the manual model of these ECVTs (if at all like the PDW motor of the TM-B) will be the gateway feature into the high-end EMTB full power space.

That said, auto mode will need more crafting to work well of us finicky riders, but theoretically auto modes could open up even more capability as time goes on. That AI camera is one way to advance this further. To be able to better predict gear changes using the same vision-based Inverse RL machine learning like Tesla Autopilot (haters aside), means you can negotiate even more challenging climbs (downshifting), going faster in downhills (upshifting), and handling turns/berms (not shifting). By sampling your very own cadence, pedal torque and gear shifts in manual mode while also sampling the visuals of the trails you ride and gyroscopic sensing, that can be used to train the onboard AI. Over time, the bike will learn and become like a prosthetic extension your riding experience.

This may all sound a bit scary, but things like predictive AI auto modes, battery regen, traction control, ABS braking will find their way onto our EMTBs in the future. I got a got a good taste of that future with the TM-B and can’t wait. Take heart though, as I still have my meat bikes as pallet cleansers.

 

[Red Peekay]

While that post is for the MG instead of the X1P, the innovation is felt just the same. What’s really interesting it the AI camera on the Mondraker prototype:

View attachment 187903

I’ve test the Rivian/Also TM-B and one of the boatload of high tech features on that bike was its virtual manual shifting mode. I was blown away on how instantaneous and precise it felt (including haptic feedback), and it really made the e-mobility aspect of the bike feel like an actual EMTB on the technical trails. I’m certain the manual model of these ECVTs (if at all like the PDW motor of the TM-B) will be the gateway feature into the high-end EMTB full power space.

That said, auto mode will need more crafting to work well of us finicky riders, but theoretically auto modes could open up even more capability as time goes on. That AI camera is one way to advance this further. To be able to better predict gear changes using the same vision-based Inverse RL machine learning like Tesla Autopilot (haters aside), means you can negotiate even more challenging climbs (downshifting), going faster in downhills (upshifting), and handling turns/berms (not shifting). By sampling your very own cadence, pedal torque and gear shifts in manual mode while also sampling the visuals of the trails you ride and gyroscopic sensing, that can be used to train the onboard AI. Over time, the bike will learn and become like a prosthetic extension your riding experience.

This may all sound a bit scary, but things like predictive AI auto modes, battery regen, traction control, ABS braking will find their way onto our EMTBs in the future. I got a got a good taste of that future with the TM-B and can’t wait. Take heart though, as I still have my meat bikes as pallet cleansers.

I just can't wait for the day when I mind meld with the bike... no AI camera needed...it just knows... it even loads itself onto the back of the car when I'm thinking about going for a ride

Bring it on!

 

[jeanjean]

And with the camera you can control your FOX live valve suspension

not the speek about autonomous modes.

Maybe we will see unmanned emtvs erring through the woods in a close future

 

[DylanJM]

This may all sound a bit scary, but things like predictive AI auto modes, battery regen, traction control, ABS braking will find their way onto our EMTBs in the future. I got a got a good taste of that future with the TM-B and can’t wait. Take heart though, as I still have my meat bikes as pallet cleansers.

The way normal mtb riders currently look at emtb riders is how I look at emtb riders who want this stupid shite on their bike.

 

[slickrock]

The way normal mtb riders currently look at emtb riders is how I look at emtb riders who want this stupid shite on their bike.

Like the same way EMTB is taking over MTB where pink bikers just can't stand it. And so the cycle continues. Next year at Sea Otter there will be high-tech bikes like this to demo, touted as the premier models from the very same brands we respect. May not have visual AI-assistance (a bit fanciful, but will bring out the paranoid), but it's coming for you, yeah it's coming for you. All the other kids with the pumped up bikes better run, run, run, out run my...

 

[jeanjean]

I went riding yesterday, and took a bit of attention to my cadence.

Usual cadence 90-95 rpm
On the flat 80-85 rpm
On short steep uphills up to 100-120 rpm

What I would greatly appreciate on my future ecvt-emtb is a thumb activated remote or shifter for quickly change the target cadence "on the fly".

I think I don't need a manual shift mode with fix ratios because I would loose a big advantage of the ecvt which is to always provide an adequate gear ratio.

But to be able to quickly change the target cadence would really be a big help.

Really looking forward to those bikes!

 

[emtbeast]

I went riding yesterday, and took a bit of attention to my cadence.

Usual cadence 90-95 rpm
On the flat 80-85 rpm
On short steep uphills up to 100-120 rpm

What I would greatly appreciate on my future ecvt-emtb is a thumb activated remote or shifter for quickly change the target cadence "on the fly".

I think I don't need a manual shift mode with fix ratios because I would loose a big advantage of the ecvt which is to always provide an adequate gear ratio.

But to be able to quickly change the target cadence would really be a big help.

Really looking forward to those bikes!

I think you're missing the point of the e-cvt. The main advantage will be that you will be able to set to:

1. Cadence based assistance - You set your preferred cadence and the drive adjusts the amount of assistance to the terrain, trying to maintain the set cadence.

2. Speed based assistance - You set your preferred speed and the drive adjusts assistance and your cadence to an optimum trying to maintain preset speed.

3. Manual shift assistance(what you want), you pedal like now cadence and speed based on terrain and you shift up/down just like now, the only difference being the virtul shift occur inside the drive(not the cassette anymore).

4. Automatic assistance - bassicaly self explanatory. The drive adapts assistance based on your inputs and terrain and a predefined algorithm.

5. Auto/Manual mixed assistance - IMO the most interesting feature. In example, imagine a car driving in Automatic mode, but you are also able to manual shift down/up instantly with paddles if needed. You could have an Trail Auto/Manual or Flat Auto/Manual...

Some of these modes will most probably be pretty power hungry as the MG1 ratio control motor will have to work pretty hard to keep up will mtb like terrain and the ever changing rider inputs...but the possibilities are endless.

 

[ArmyOfEvilRobots]

This was my thinking also. And the fact that the second motor needs to be strong (torquie) enough to oppose/control the output of the first motor, although with a gearing advantage. Add this to the torque potentially produced from the human on the pedals.
I guess technically, the second motor does not need to contribute much POWER (torque x rpm) but it will have to produce enough torque to allow control, and enough rpm to produce the gear ratio desired. I think electrical motors that can produce good torque, are still able to rotate at decent speeds, so you ay as well spin it up.

The second motor needs to be strong enough to oppose the input torque it encounters, but that means it needs to resist a fraction of the torque of the primary motor. It runs at (potentially higher RPM and) lower torque because it spins the sun gear. The primary motor needs to spin the output ring.

Here's a diagram that shows where MG1/MG2 are connected, where you can see the smaller windings. Note how the MG1 only drives the sun gear, but MG2 drives the output, thereby requiring higher torque (yeah, it's another car pic, but there aren't any good diagrams for bike MGUs yet):